The present invention relates generally to satellite communication systems, and more particularly to an improved method for pointing an antenna subsystem associated with a moving platform towards a satellite in a satellite communication system.
Broadband data and video services, on which our society and economy have grown to depend, have heretofore generally not been readily available to users onboard mobile network platforms such as cars, buses, boats, trains, airplanes, etc. While the technology exists to deliver such services to most forms of mobile network platforms, past solutions have been generally quite expensive, with low data rates and/or available to only very limited markets of government/military users and some high-end maritime markets (i.e., cruise ships).
Satellite communication systems are commonly used to provide broadband data services to mobile network platforms. One obstacle in such communication systems is accurately pointing the antenna system residing on a moving platform towards a stationary satellite without degrading the performance of the communication link.
It is, therefore, a principal object of the present invention to provide a method for accurately pointing an antenna subsystem on a moving platform towards a satellite without degrading the performance of the communication link.
In accordance with the present invention, an improved method is provided for pointing an antenna subsystem residing on a mobile platform towards a satellite in a satellite communication system. The improved method includes: transmitting a tone signal from the satellite; receiving the tone signal at the antenna subsystem; determining position of the mobile platform in relation to the satellite a monopulse tracking technique, where the position of the satellite is based on the tone signal received at the antenna subsystem; and pointing the antenna subsystem towards the satellite.
In another aspect of the present invention, a reflector antenna subsystem is adapted to receive a monopulse tracking signal. The reflector antenna subsystem includes: a primary reflector; a feed device disposed on a surface of the primary reflector; a sub-reflector coupled by one or more support arms to the primary reflector, such that the subreflector is suspended above the feed device; and a second antenna disposed on an outwardly facing surface of the sub-reflector, thereby orientated to receive the monopulse tracking signal.